1. Field of the Invention
The present invention relates to a logical gate circuit. More particularly, it relates to a logical gate circuit which provides a bipolar transistor at the output stage, such as a TTL gate circuit.
2. Description of the Related Art
In a conventional logical gate circuit using a bipolar transistor, for example a TTL gate circuit, a bipolar transistor having a high drive capacity, and in particular, a bipolar transistor having a vertical construction, is suitable for rapidly switching a large current. As the TTL circuit provides an emitter grounded type inverter using such a bipolar transistor at the output stage, high speed and large current switching capacity are possible and a capacitive load can be used.
However, such a conventional logical gate circuit has some drawbacks, for example, when the inverter transistor at the output stage is ON, the base current and the collector current continuously flow, resulting in high power dissipation.